B101011 exam 1: Chapter 13, 14, and 15
10) Which of the following best expresses the concept of natural selection? A) differential reproductive success based on inherited characteristics B) inheritance of acquired characteristics C) change in response to need D) a process of constant improvement, leading eventually to perfection
A
11) Which of the following assumptions or observations is not part of Darwin's idea of natural selection? A) Whether an organism survives and reproduces is almost entirely a matter of random chance. B) Heritable traits that promote successful reproduction should gradually become more common in a population. C) Populations produce more offspring than their environment can support. D) Organisms compete for limited resources.
A
15) Which of the following would prevent an organism from becoming part of the fossil record when it dies? A) It is fully decomposed by bacteria and fungi. B) It is buried in fine sediments at the bottom of a lake. C) It gets trapped in sap. D) It is frozen in ice.
A
21) Diane Dodd raised different fruit fly populations on different food sources. She found that after about 40 generations the evolution of reproductive isolation was under way. The mechanism of evolution responsible for this was A) natural selection. B) genetic drift. C) gene flow. D) mutation.
A
22) A population is A) a group of individuals of the same species that live in the same area and interbreed. B) all individuals of a species, regardless of location or time period in which they live. C) a group of individuals of different species living in the same place at the same time. D) a group of individuals of a species plus all of the other species with which they interact.
A
24) Speciation without geographic isolation is called ________ speciation. A) sympatric B) allopatric C) incomplete D) diversifying
A
24) The ultimate source of all new alleles is A) mutation. B) chromosomal duplication. C) genetic drift. D) natural selection.
A
28) Sympatric speciation commonly occurs through ________ in plants but is more likely to occur through ________ in animals. A) polyploidy; habitat differentiation and sexual selection B) habitat differentiation and sexual selection; polyploidy C) asexual reproduction; chromosome duplications D) self-pollination; polyploidy and other genetic mechanisms
A
32) The emergence of many diverse species from a common ancestor is called A) adaptive radiation. B) gradualism. C) allopatric speciation. D) hybridization.
A
39) A rabbit population consists of animals that are either very dark on top or very light on top. The color pattern is not related to sex. No rabbit shows intermediate coloration (medium darkness). This pattern might result from A) disruptive selection. B) directional selection. C) stabilizing selection. D) sexual selection.
A
4) Darwin found that many of the species on the Galápagos islands A) resembled species on the nearest mainland. B) resembled species in Europe. C) resembled species from Australia. D) were identical to South American species.
A
4) Miller was the first to show that A) amino acids and other organic molecules could have formed under conditions thought to resemble those of early Earth. B) the earliest forms of life were photosynthetic. C) eukaryotic life evolved from early prokaryotes. D) the earliest forms of life had an RNA genome.
A
40) Which of the following descriptions best represents the gradual model of speciation? A) Speciation occurs regularly as a result of the accumulation of many small changes. B) An isolated population differentiates quickly from its parent stock as it adapts to its local environment. C) Speciation occurs under unusual circumstances and therefore transitional fossils are hard to find. D) Species undergo little change over long periods interrupted only by short periods of rapid change.
A
41) Mate-attracting features such as the bright plumage of a male peacock result from A) intersexual selection. B) intrasexual selection. C) disruptive selection. D) stabilizing selection.
A
41) One of the finest available sequences of fossils shows how horses have changed slowly and by subtle steps from small shrub-browsing ancestors to the large, grass-grazing modern horse. A large number of fossil species have been named, and it is often difficult to decide on the identity of a fossil horse because transitional forms are common. This record of evolution best fits the idea of A) the gradual model of speciation. B) punctuated equilibrium. C) adaptive radiation. D) hybrid breakdown.
A
44) Allopatric speciation is not likely to occur when A) there is no disruption in gene flow between two populations. B) a geographic barrier forms between two populations. C) several populations become isolated from one another as drying conditions cause a large body of water to become separate smaller bodies of water. D) separated populations adapt to different environmental conditions.
A
44) Which of the following would most quickly be eliminated by natural selection? A) a harmful allele in an asexual, haploid population B) a harmful recessive allele in a sexual, diploid population C) a harmful recessive allele in a sexual, polyploid population D) any harmful allele, regardless of the system of inheritance in a population
A
46) Speciation often occurs when a habitat becomes more heterogeneous. In Lake Victoria different species of cichlids are found in different areas of the lake. The best explanation for this speciation is that A) natural selection favored different heritable variations in different parts of the lake. B) male cichlids that lived in deep water needed to be seen by females, so they became colorful. C) food was scarce in the lake, so some fish had to learn how to scrape algae, some had to learn to eat insects, and some had to learn to bite leaves. D) humans selected for many different traits in cichlids in order to market them to the aquarium trade.
A
47) A new plant species may arise in a single generation by A) errors in meiosis leading to polyploidy. B) a sudden geological disruption causing separation of two populations. C) mutations in genes for flower color. D) changes in the pollinator species.
A
48) For speciation to occur there must be A) sexual reproduction. B) genetic variation. C) isolation. D) natural selection.
A
49) In a population of plants with a diploid number of 12, a new individual appeared with a chromosome number of 24. If this organism could self-fertilize, forming offspring with the same number of chromosomes (24), scientists would consider this an example of A) sympatric speciation. B) behavioral isolation. C) formation of a hybrid zone. D) reduced hybrid fertility.
A
8) Which of the following types of reproductive barriers separates a pair of species that could interbreed but for the fact that one mates at dusk and the other at dawn? A) temporal isolation B) habitat isolation C) behavioral isolation D) mechanical isolation
A
9) Broccoli, cabbages, and Brussels sprouts all descend from the same wild mustard and can still interbreed. These varieties were produced by A) artificial selection. B) natural selection. C) genetic drift. D) inheritance of acquired characteristics.
A
1) Blue-footed boobies have webbed feet and are comically clumsy when they walk on land. Evolutionary scientists view these feet as A) an example of a trait that is poorly adapted. B) the outcome of a trade-off: Webbed feet perform poorly on land, but are very helpful in diving for food. C) an example of a trait that has not evolved. D) a curiosity that has little to teach us regarding evolution.
B
1) Speciation, or the formation of new species, is A) a form of microevolution. B) responsible for the diversity of life. C) necessary for natural selection and adaptation. D) an event that has occurred only a few times in the history of the planet.
B
1) The "big bang" that produced the universe is thought to have occurred A) 40 to 50 billion years ago. B) 12 to 14 billion years ago. C) 4.6 billion years ago. D) 4 million years ago.
B
10) Which of the following types of reproductive barriers separates a pair of moth species that could interbreed but for the fact that the females' mating pheromones are not attractive to the males of the other species? A) temporal isolation B) behavioral isolation C) mechanical isolation D) gametic isolation
B
12) Which of the following thinkers argued that much of human suffering was the result of human populations increasing faster than food supply, an argument that later influenced Charles Darwin's ideas of natural selection? A) Charles Lyell B) Thomas Malthus C) Jean-Baptiste Lamarck D) Gregor Mendel
B
13) A dog breeder wishes to develop a breed that does not bark. She starts with a diverse mixture of dogs. Generation after generation, she allows only the quietest dogs to breed. After 30 years of work she has a new breed of dog with interesting traits, but on average, the dogs still bark at about the same rate as other dog breeds. Which of the following would be a logical explanation for her failure? A) There is no variation for the trait (barking). B) The tendency to bark is not a heritable trait. C) The selection was artificial, not natural, so it did not produce evolutionary change. D) There was no selection (differential reproductive success) related to barking behavior.
B
14) Two species that sometimes mate and produce vigorous but sterile offspring are affected by A) gametic isolation. B) reduced hybrid fertility. C) reduced hybrid viability. D) hybrid breakdown.
B
14) Which of the following statements regarding natural selection is false? A) Natural selection depends on the local environment at the current time. B) Natural selection starts with the creation of new alleles that are directed toward improving an organism's fitness. C) Natural selection and evolutionary change can occur in a short period of time (a few generations). D) Natural selection can be observed working in organisms alive today.
B
16) Frequently, a group of related species will each have a unique courtship ritual that must be performed correctly for both partners to be willing to mate. Such a ritual constitutes a ________ ________ reproductive barrier. A) mechanical; postzygotic B) behavioral; prezygotic C) temporal; prezygotic D) gametic; postzygotic
B
17) The Monterey pine and the Bishop's pine inhabit some of the same areas of central California. The Monterey pine releases pollen in February, while the Bishop's pine does so in April. This is an example of ________ isolation. A) postzygotic B) temporal C) habitat D) mechanical
B
18) Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species; both species have four limbs with a similar skeletal structure; the species' early embryos are very similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In evolutionary terms, these are examples of A) geographic similarity. B) homology. C) adaptation by natural selection. D) coincidental similarity.
B
19) Uplift and formation of a mountain range divide a freshwater snail species into two isolated populations. Erosion eventually lowers the mountain range and brings the two populations together again, but when they mate, the resulting hybrids all produce sterile young. This scenario is an example of A) sympatric speciation. B) allopatric speciation. C) incomplete speciation. D) diversifying speciation.
B
19) Which of the following represents a pair of homologous structures? A) the wing of a bat and the scales of a fish B) the wing of a bat and the flipper of a whale C) the antennae of an insect and the eyes of a bird D) the wing of a bat and the wing of a butterfly
B
2) The earliest discovered fossils are of ________ dating back to ________ years ago. A) single-celled eukaryotes; 4.5 billion B) prokaryotes; 3.5 billion C) algae; 1 billion D) fish; 600 million
B
20) What evidence is used to determine the branching sequence of an evolutionary tree? A) experiments in artificial selection B) anatomical or molecular homologous structures C) the genetic code D) an overall assessment of general similarities between organisms
B
25) Organisms that possess more than two complete sets of chromosomes are said to be A) haploid. B) polyploid. C) diploid. D) hybrids.
B
30) Which of the following statements about plant speciation and hybridization is false? A) Plant biologists estimate that 80% of all living plant species are descended from ancestors that formed by polyploid speciation. B) Bread wheat is the ancestral diploid wheat plant. C) Modern plant geneticists use chemicals to induce meiotic and mitotic errors to try to create new hybrid plants with special qualities. D) Bread wheat grown widely today is the result of several hybridization events.
B
31) Which of the following statements about the Galápagos finches is false? A) The Galápagos finch species differ in their feeding habitats. B) Each island in the Galápagos chain has one and only one isolated, unique species of Darwin's finch. C) Most speciation events of the Galápagos finches occurred when some finches made it to another island, evolved in isolation, and accumulated enough changes to become a new species. D) The evolution of the Galápagos finches is an excellent example of adaptive radiation.
B
33) Which of the following would tend to promote adaptive radiation? A) An organism has a very stable set of features and capabilities over long spans of evolutionary time. B) An organism colonizes an isolated area that is habitable but relatively devoid of life. C) An organism colonizes an area that already has a high level of existing species diversity. D) A single species goes extinct, but it has several competitors that quickly expand to assume its ecological roles.
B
35) Two bird species overlap in a hybrid zone. They are isolated by a slight difference in the male songs and by the females' tendency to select males with the "correct" song. Hybrid offspring tend to have reduced fertility compared to either of the parent species. What effect might natural selection have in this situation? A) Natural selection might favor males with less distinctive calls and/or females that are less "choosy." B) Natural selection might favor males with more distinctive calls and/or females that are more "choosy." As a result, the reproductive barrier between the two species could be reinforced. C) Natural selection could lead to the hybrid species taking over and eliminating the weaker parent species. D) Natural selection could lead to the stronger of the two species taking over and eliminating the other species.
B
36) In a hybrid zone, ________ can occur if the reproductive barrier between two species is weak, as seen among cichlids in the murky waters of modern Lake Victoria. A) reinforcement B) fusion C) allopatric speciation D) reproductive isolation
B
37) An elk herd is observed over many generations. Most of the full-grown bull elk have antlers of nearly the same size, although a few have antlers that are significantly larger or smaller than this average size. The average antler size remains constant over the generations. Which of the following effects probably accounts for this situation? A) directional selection B) stabilizing selection C) a bottleneck effect that resulted in low genetic diversity D) a high rate of gene flow
B
39) One of the key contributions of the punctuated equilibrium model is that it helps explain A) why transitional fossils are more common than Darwin would have predicted. B) why transitional fossils tend to be rare and certain common fossil species remain unchanged for long time spans. C) how new species arise from hybridization events. D) why large, widespread populations tend to be the ones that evolve most rapidly and unpredictably.
B
40) Large antlers in male elk, which are used for battles between males, are a good example of a trait favored by A) intersexual selection. B) intrasexual selection. C) disruptive selection. D) stabilizing selection.
B
42) The fossil record shows that for many plant and animal groups, the time between speciation events A) is usually about 50,000 years. B) varies greatly, but averages 6.5 million years. C) is usually greater than 40 million years. D) is equivalent to the length of one hundred generations of a species.
B
45) The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural selection eliminate this allele from all human populations? A) Natural selection is a positive force, so it does not eliminate alleles. B) In populations where endemic malaria is present, heterozygotes have an important advantage: They are resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele. C) Mutations keep bringing the allele back into circulation. D) Natural selection occurs very slowly, but elimination of the sickle-cell allele is expected to occur soon.
B
46) Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika, tends to A) eliminate rare alleles and favor whichever allele is initially most frequent. B) maintain two phenotypes in a dynamic equilibrium in a population. C) produce random changes in allele frequencies. D) stimulate new mutations.
B
47) Tay-Sachs is inherited as an autosomal recessive allele. Homozygous individuals die within the first few years of life. However, there is some evidence that heterozygous individuals are more resistant to tuberculosis. Which of the following statements about Tay-Sachs is true? A) The allele for Tay-Sachs is selected against. B) This situation is an example of heterozygote advantage if tuberculosis is present in a population. C) This situation is an example of disruptive selection. D) Heterozygotes will be more fit than either homozygote regardless of environmental conditions.
B
48) Some of your DNA may not code for any protein and has no known function in gene regulation; it is sometimes referred to as "junk" DNA. How do nucleotide sequences of "junk DNA" evolve? A) They evolve through natural selection. B) They evolve through genetic drift and other chance processes. C) They evolve to be more useful by taking on new functions. D) They evolve by gradually being eliminated from the gene pool.
B
52) A group of dog breeders is trying to design and develop an ideal dog. They want a dog with a gentle disposition, black fur, long ears, short legs, and a strong sense of smell. Which of the following comments from fellow dog breeders represents the biggest challenge they are likely to face? A) There are breeds with long ears and breeds with short leg, but no breeds with both. B) There does not seem to be any genetic variation in sense of smell. C) Artificial selection is artificial and cannot change the genetics of a breed like natural selection. D) Most dogs with black fur have long legs.
B
55) Which of the following statements about adaptation is true? A) An individual that has learned how to survive cold winters has become adapted to the cold. B) A population that has an increase in frequency of alleles for thicker fur has become adapted to the cold. C) Adaptation results when cold temperatures cause mutations for longer fur. D) Adaptation is possible when all the alleles in a gene pool are the same.
B
58) A news article discussing the evolution of domestic dogs from wolves included this statement: "On its way from pack-hunting carnivore to fireside companion, dogs learned to love—or at least live on—wheat, rice, barley, corn, and potatoes." What is a more scientifically accurate way to state what happened with dogs? A) Dogs mutated to be able to eat wheat, rice, barley, corn, and potatoes. B) Some wolves may have had variants in their digestion that allowed them to eat wheat, rice, barley, corn, and potatoes and so were able to survive with humans. C) Being around humans represented an advantage, so wolves were able to take advantage of that by changing their digestion to be able to eat wheat, rice, barley, corn, and potatoes. D) Dogs were created at the same time as wolves.
B
6) Which provides the most general and correct description of the idea of a reproductive barrier? A) any feature (of geography, behavior, or morphology) that keeps one species from mating with another B) a biological difference between two species that prevents them from successfully interbreeding C) a geographic barrier that separates two species and prevents gene flow between them D) a difference in behavior that keeps two species from interbreeding
B
6) Who developed a theory of evolution almost identical to Darwin's? A) Lyell B) Wallace C) Aristotle D) Lamarck
B
9) Which of the following types of reproductive barriers separates a pair of insect species that could interbreed but for the fact that one lives on goldenrod plants and the other on autumn daisies in the same general area? A) temporal isolation B) habitat isolation C) behavioral isolation D) gametic isolation
B
11) Which of the following types of reproductive barriers separates two flowering plant species that could interbreed but for the fact that one has a deep flower tube and is pollinated by bumblebees whereas the other has a short, narrow flower tube and is pollinated by honeybees? A) habitat isolation B) behavioral isolation C) mechanical isolation D) gametic isolation
C
13) Two species that occasionally mate and produce zygotes, but that have incompatible genes that prevent the resulting embryo from developing, are affected by A) gametic isolation. B) reduced hybrid fertility. C) reduced hybrid viability. D) hybrid breakdown.
C
17) Which of the following disciplines has found evidence for evolution based on the native distributions (locations) of living species? A) molecular biology B) comparative anatomy C) geographic distribution D) paleontology
C
18) The geographic isolation of a population from other members of the species and the subsequent evolution of reproductive barriers between it and the parent species describes ________ speciation. A) punctuated B) sympatric C) allopatric D) biogeographic
C
2) The core theme of biology, which explains both the unity and diversity of life, is A) genetics. B) ecology. C) evolution. D) metabolism.
C
21) Darwin was the first person to draw an evolutionary tree, a diagram that represents A) records of breeding in domesticated animals. B) records of lineages in humans (also known as a family tree). C) evidence-based hypotheses regarding our understanding of patterns of evolutionary descent. D) groupings of organisms based on overall similarity.
C
22) Diane Dodd's experiments using fruit flies demonstrated that A) the evolution of reproductive barriers occurs much too slowly to produce measurable effects in the laboratory. B) new species can form in a single generation by the production of new reproductive structures. C) formation of a reproductive barrier between two populations is more likely if they experience and adapt to different environmental conditions. D) reproductive barriers usually are absolute: Either two populations are fully willing and able to interbreed, or they are strictly separated by a fully effective reproductive barrier.
C
29) Ancestral diploid wheat species had 2n = 14 chromosomes. What happened when two of these species hybridized? A) They produced a viable, fertile hybrid species with 14 chromosomes. B) They produced a hybrid species that could not complete mitosis, so it did not develop properly. C) They produced a hybrid species with 14 chromosomes that was sterile because the chromosomes from the two different parent species did not pair up properly in meiosis. D) They produced a hybrid species with 28 chromosomes.
C
3) Aristotle believed that A) species evolve through natural selection and other mechanisms. B) an individual's use of a body part causes it to further evolve. C) species are fixed (permanent) and perfect. D) the best evidence for change within species is seen in fossils.
C
36) Which of the following will tend to produce adaptive changes in populations? A) genetic drift B) gene flow C) natural selection D) the founder effect
C
38) After a copper smelter begins operation, local downwind populations of plants begin to adapt to the resulting air pollution. Scientists document, for example, that the acid tolerance of several plant species has increased significantly in the polluted area. This is an example of A) stabilizing selection. B) disruptive selection. C) directional selection. D) genetic drift.
C
38) The emergence of a new plant species over a brief period of time followed by a long period of little change is consistent with which of the following theories? A) the gradual model of speciation B) allopatric speciation C) punctuated equilibrium D) adaptive radiation
C
43) Speciation has occurred when A) two populations of organisms have been separated for a very long time. B) a change in allele frequency has occurred. C) organisms of one population do not recognize the mating call of another population and so mating does not occur. D) offspring of mating from members of two different populations are able to mate with members of either population.
C
45) Two populations that have been separated by a river are most likely to become separate species if A) fur color is different in the two populations. B) genes controlling ear development become different so that members of one population have much longer ears than the other. C) genes controlling molecules on the surface of the sperm that bind with egg receptors are different in the two populations. D) feeding habits are different in the two populations.
C
49) Mothers and teachers often say they need another pair of eyes on the backs of their heads. And another pair of hands would come in handy in many situations. You can imagine that these traits would have been advantageous to our early hunter-gatherer ancestors as well. According to sound evolutionary reasoning, what is the most likely explanation for why humans do not have these traits? A) Because they actually would not be beneficial to the fitness of individuals who possessed them. Natural selection always produces the most beneficial traits for a particular organism in a particular environment. B) Because every time they have arisen before, the individual mutants bearing these traits have been killed by chance events. Chance and natural selection interact. C) Because these variations have probably never appeared in a healthy human. As tetrapods, we are pretty much stuck with a four-limbed, two-eyed body plan; natural selection can only edit existing variations. D) Because humans are a relatively young species. If we stick around and adapt for long enough, it is inevitable that the required adaptations will arise.
C
5) Lyell's book Principles of Geology, which Darwin read on board the H.M.S. Beagle, argued in favor of which of the following concepts? A) Earth's surface is shaped mainly by occasional catastrophic events. B) Meteorite impacts may have been a major cause of periodic mass extinctions. C) Earth's surface is shaped by natural forces that act gradually and are still acting. D) The processes that shape Earth today are very different from those that were at work in the past.
C
5) Which of the following statements regarding the definition of species is false? A) The ecological species concept identifies species in terms of their ecological niches. B) The phylogenetic species concept defines a species as a set of organisms that shares a common ancestor and forms one branch on the tree of life. C) The morphological species concept relies upon comparing the DNA sequences of organisms. D) Under the biological species concept, the gap between species is maintained by reproductive isolation.
C
50) In a large population of plants, notches in the leaves are caused by a dominant allele N and lack of notches by a recessive allele n. Over many generations the proportion of plants in the population with notched leaves increases. What is the most likely cause? A) Dominant alleles generally increase in frequency over time. B) The recessive alleles were all masked by the dominant alleles. C) Directional selection favored plants with notched leaves. D) Genetic drift caused a steady movement toward a greater proportion of plants with notched leaves.
C
53) A farmer decides to go into the business of raising trout for tourists who enjoy fishing. She builds six trout ponds and stocks each of them with trout from genetically identical stock. Her friends tell her that because she started each pond with just a few trout, she has created a bottleneck effect and her trout populations are likely to become genetically different rapidly. Which of the following statements about her trout is likely true? A) Because they are all genetically alike, they will all remain alike even though the ponds are different. B) Because each population started off with just a few individuals, every mutation that occurs will have a huge impact on the population, so they are likely to evolve in different directions quickly. C) Because the ponds are different and the populations are likely to experience different mutations, the populations will likely diverge evolutionarily, but only over many generations. D) The increase in genetic diversity caused by sexual reproduction will promote evolutionary divergence over time.
C
57) Which of the following statements regarding fins on fishes is true? A) Fins evolved so that fish could swim better. B) Fins came about because animals couldn't live in water without them. C) Fins are an adaptation that aid in swimming. D) Fins resulted from a mutation caused by a movement from land to water.
C
7) Which of the following statements would Darwin have disagreed with? A) Species change over time. B) Living species have arisen from earlier life-forms. C) Descent with modification occurs through inheritance of acquired characteristics. D) Descent with modification occurs by natural selection.
C
8) During the 1950s, a scientist named Lysenko tried to solve the food shortages in the Soviet Union by breeding wheat that could grow in Siberia. He theorized that if individual wheat plants were exposed to cold, they would develop additional cold tolerance and pass it to their offspring. Based on the ideas of artificial and natural selection, do you think this project worked as planned? A) Yes; the wheat probably evolved better cold tolerance over time through inheritance of acquired characteristics. B) No, because Lysenko took his wheat seeds straight to Siberia instead of exposing them incrementally to cold. C) No, because there was no process of selection based on inherited traits. Lysenko assumed that exposure could induce a plant to develop additional cold tolerance and that this tolerance would be passed to the plant's offspring. D) Yes, because this is generally the method used by plant breeders to develop new crops.
C
12) Which of the following types of reproductive barriers separates two species of sea cucumbers whose sperm and eggs often bump into each other but do not cross-fertilize because of incompatible proteins on their surfaces? A) temporal isolation B) habitat isolation C) mechanical isolation D) gametic isolation
D
15) Two species interbreed occasionally and produce vigorous, fertile hybrids. When the hybrids breed with each other or with either parent species, however, the offspring are feeble or sterile. These species are affected by A) gametic isolation. B) reduced hybrid fertility. C) reduced hybrid viability. D) hybrid breakdown.
D
16) Which of the following statements regarding the currently available fossil record is false? A) The currently available fossil record shows that the earliest fossils of life are about 3.5 billion years old. B) The currently available fossil record shows that younger strata were laid down on top of older strata. C) The currently available fossil record documents gradual evolutionary changes that link one group of organisms to another. D) The currently available fossil record shows that the first life-forms were eukaryotes.
D
2) Which of the following would a biologist describe as microevolution? A) the formation of new species B) the extinction of species C) dramatic biological changes, such as the origin of flight, within a taxon D) a change in the gene pool of a population from one generation to the next
D
20) In which of the following situations would speciation be most likely to occur? A) A population of juniper shrubs is split in two by a canyon. Every year, strong winds carry a small amount of the shrubs' pollen across the canyon. B) A Japanese mollusk species whose larvae are often carried from port to port in ship bilge (waste) water now flourishes in San Francisco Bay, a busy commercial port. C) Bighorn sheep occupy mountains from Canada to Death Valley in Southern California, interbreeding all the way. The populations at the two ends of the range live in very different environments. D) Seven monkeys escape from an enclosure. To everyone's surprise, they establish a small but viable population, coexisting successfully with humans in a partly suburban environment very different from their native African habitat.
D
23) Microevolution, or evolution at its smallest scale, occurs when A) an individual's traits change in response to environmental factors. B) a community of organisms changes due to the extinction of several dominant species. C) a new species arises from an existing species. D) a population's allele frequencies change over a span of generations.
D
23) When plants undergo allopatric speciation, an initial reproductive barrier is often A) polyploidy. B) gametic isolation. C) temporal isolation. D) pollinator choice.
D
26) Most polyploid species arise from A) a single diploid parent plant. B) a single triploid parent plant. C) a single tetraploid parent plant. D) the hybridization of two parent species.
D
27) When a tetraploid flower pollinates a diploid flower of the parental species, the resulting offspring will be A) pentaploid and sterile. B) diploid and fertile. C) triploid and fertile. D) triploid and sterile.
D
3) The findings of Pasteur and others have established that A) living organisms regularly self-assemble (arise spontaneously) from nonliving matter. B) living organisms do not arise from nonliving matter today, nor did they arise from nonlife in the past. C) advanced organisms cannot arise from nonliving matter, but simple microbial life often does arise from nonlife today. D) life does not arise from nonliving matter today, but in the conditions of early Earth, such an event could have occurred.
D
3) Under the biological species concept, a species is a group of organisms that A) are physically similar. B) share a recent common ancestor. C) live together in a location and carry out identical ecological roles. D) have the potential to interbreed in nature and produce fertile offspring.
D
34) A group of ants escaped from a picnic basket carried to the top of a mountain and thrived in this area where there were no other ants. Many years later descendants of these ants crawled into a picnic basket on the mountain and traveled back to the valley from which their ancestors had come. Which of these observations would cause you to conclude that the ants on top of the mountain had become a different species from those in the valley? A) The mountain ants and valley ants were different colors. B) The mountain ants and valley ants were different sizes. C) The mountain ants ate different food than the valley ants. D) The mountain ants could not mate with the valley ants.
D
35) Which of the following statements best describes the true nature of natural selection? A) Only the strongest survive. B) The strong eliminate the weak in the race for survival. C) Organisms change by random chance. D) Heritable traits that promote reproduction become more frequent in a population from one generation to the next.
D
37) The ________ suggests that speciation occurs in brief spurts. A) adaptive model of the origin of species B) allopatric speciation model C) gradual model of the origin of species D) punctuated equilibrium model
D
4) The biological species concept is A) applicable to all forms of life, past and present. B) applicable to all present life-forms but not to fossil organisms whose reproductive behavior cannot be observed. C) easy to apply to all present sexually reproducing organisms but harder to apply to asexual organisms and fossils. D) sometimes difficult to put into practice even for present sexual organisms and useless for asexual organisms and fossils.
D
42) A woman struggling with a bacterial illness is prescribed a month's supply of a potent antibiotic. She takes the antibiotic for about two weeks and feels much better. Should she save the remaining two-week supply, or should she continue taking the drug? A) She should save the drug for later, because if she keeps taking it the bacteria will evolve resistance. B) She should save the drug for use the next time the illness strikes. C) She should save the drug because antibiotics are in short supply and she may need it to defend herself against a bioterrorism incident. D) She should continue taking the drug until her immune system can completely eliminate the infection. Otherwise, some bacteria may remain in her system, and they will probably be resistant.
D
43) If you were just diagnosed with a serious bacterial disease, which of these would predict the most positive outcome for treatment? The disease was acquired A) in a hospital, where most of the bacteria are probably already weakened by antibiotics in the environment. B) in a livestock barn where the animals have been treated with antibiotics. C) in a big city where antibiotics are routinely prescribed by doctors. D) in a remote, sparsely populated area where the bacteria have not been exposed to antibiotic drugs.
D
51) A population of butterflies has an allele B for big spots on the wings and b for small spots on the wings. The table below provides data about this population. Genotype BB Bb bb Number of butterflies 300 400 300 Genotype frequency 0.3 0.4 0.3 Regarding these data about the butterfly population, which of the following statements is correct? A) The population is in Hardy-Weinberg equilibrium because the number of B alleles is equal to the number of b alleles. B) The population is in Hardy-Weinberg equilibrium because half of the heterozygotes are B and half are b. C) The population is not in Hardy-Weinberg equilibrium because p2 and 2pq are different. D) The population is not in Hardy-Weinberg equilibrium because the genotype frequency of bb is greater than it would be in equilibrium.
D
56) Some butterflies can ingest toxic chemicals from the milkweed plants they feed on and then can store those chemicals in their body. Because toxins stored in the butterflies are toxic to birds, the birds avoid eating the butterflies. Which of the following is the best explanation for this situation? A) Butterflies that stored the chemicals were never eaten by predators, so those butterflies survived. B) Butterflies developed a mutation that led them to be able to store the chemical because they needed to avoid being eaten. C) Milkweed plants wanted the butterflies to ingest the chemical so they would no longer feed on the plant, but the butterflies fooled the milkweed by storing the toxic chemicals. D) Any butterfly allele that allowed milkweed toxin storage would be likely to persist because butterflies that had it were more likely to survive.
D
7) Two populations of organisms belong to the same biological species when they A) cannot mate with each other because mating occurs at different times. B) use different types of behaviors or physical features to attract mates. C) have anatomical features that make it difficult for organisms from the two populations to mate with one another. D) encounter each other, mate, and produce viable, fertile offspring under natural conditions.
D
